Effect of working length measurement by electronic apex locator or radiography on the adequacy of final working length: a randomized clinical trial

Abstract

Introduction: Obtaining a correct working length is critical to the success of endodontic therapy. The aim of this clinical study was to compare the effect of working length determination using electronic apex locator or working length radiograph on the length adequacy of final working length as well as the final obturation.

Methods: A total of 84 patients with 188 canals were randomized into two groups; in group 1, the working length was determined by working length radiograph, whereas in group 2, it was determined by the Raypex5 electronic apex locator (VDW, Munich, Germany). Length adequacy was assessed in each group for master cone and final obturation radiography and categorized into short, acceptable, and over cases.

Results: There was no statistically significant difference between the rates of acceptable (master cone radiography: group 1 = 82.1% and group 2 = 90.4%; final radiography: group 1 = 85.7% and group 2 = 90.4%) and short cases (master cone radiography: group 1 = 7.1% and group 2 = 8.7%; final radiography: group 1 = 1.2% and group 2 = 1%) between the two groups. Over cases in master cone radiography were significantly more in group 1 (10.7%) than group 2 (1%) (χ², p = 0.00). However, this category did not show a significant difference for final obturation between group 1 (13.1%) and group 2 (8.7%).

Conclusion: The results of endodontic treatment using the Raypex5 electronic apex locator are quite comparable, if not superior, to radiographic length measurement regarding the rates of acceptable and short cases. Furthermore, in addition to reducing the radiographic exposure, electronic apex locators are superior in reducing overestimation of the root canal length.